The present invention relates to a method and a device for controlling an internal combustion engine.
A method and a device for controlling an internal combustion engine are described in U.S. Pat. No. 5,235,949 (German Patent No. 39 25 877). At least one temperature variable and one pressure variable are measured by sensors. On the basis of the temperature variable and the pressure variable, the air mass is determined that is supplied to the internal combustion engine. Alternatively, the air mass may be directly detected by a sensor.
The continuous calculation of the air mass on the basis of temperature and pressure is too slow for dynamic operation since the dynamic response of the temperature sensor is generally too low. However, a sensor detecting, for example, the air mass, may be subjected to drift or aging over the operating time. Moreover, it is possible for this sensor to fail.
An object of the present invention is to provide a method and a device for controlling an internal combustion engine that provides as accurate a signal as possible with regard to the air mass. Furthermore, it should be guaranteed that, in the case of a failure of the sensor, a substitute signal that has sufficient accuracy is available.
Using the method according to the present invention, the output signal of the air-mass meter may be corrected so that the output signal has a very high accuracy. Moreover, a substitute signal is available for the limp-home operation, for example, in the case of a failure of the air-mass meter.